FIG. 5.

Effects of nonpolar deletions of glpD (lmo1293), lmo1538, and lmo1968-1974 on the intracellular replication of L. monocytogenes. Caco-2 cells were infected with either the wild-type strain (EGD) or the mutants to an MOI of 6 to 14, and the numbers of bacteria recovered after 7 hours of infection were determined. Mutant strains with deletions of lmo1538 (Δ1538), glpD (ΔglpD), lmo1538 and glpD (Δ1538/ΔglpD), and lmo1968-1974 (Δ1968-1974) were studied. Eleven independent infections were performed for each strain. Error bars represent the standard deviations from the means. The application of the Student t test and the use of pair differences revealed significant differences in the replication efficiencies of the tested mutants from that of the wild-type strain.